Process and apparatus for preparing and dispensing coffee

ABSTRACT

A process for preparing coffee in a dispensing apparatus is described, the apparatus ( 1 ) having a feed chute ( 6 ) mounted on the supporting frame ( 2 ) and being able to rotate with respect to said frame in order to feed the ground coffee to the infusion chamber ( 3 ), wherein the feed chute ( 6 ) and the infusion chamber ( 3 ) are positioned so as to obtain a desired distribution of ground coffee in the chamber ( 3 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/IB2014/001396 filed Jul. 25, 2014, claiming priority based onEuropean Patent Application No. 13 178835.8 filed Jul. 31, 2013, thecontents of all of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The present invention concerns a process for preparing various types ofcoffee in a dispensing apparatus and a dispensing apparatus adapted forcarrying out such a process.

BACKGROUND OF THE INVENTION

For sake of description simplicity, it is herein referred to coffeeonly, but more in general the present invention refers to any beverageobtained by infusion of a substance in form of powder or particles, suchas tea, tisanes and similar, with water or other infusion liquid.

Machines for dispensing beverages are known, in particular for coffeeand beverages of the same kind, having a dispensing apparatus forpreparing coffee, where ground coffee is measured and inserted, bygravity, into an infusion chamber and then compressed by one or moremovable walls, usually one or more pistons. An infusion liquid, usuallywater, is then forced through the coffee tablet compressed into theinfusion chamber, so that the substances of the ground product areextracted and the beverage is obtained.

The amount of coffee powder to be settled inside the infusion chamberdepends on the type of desired beverage: for example, for an espresso isnecessary an amount of ground coffee much lower than the coffee amountnecessary for a so-called “American” coffee. The ground coffee is fed bygravity into the infusion chamber and tends to settle inside the chamberrandomly: in case of small coffee amount, little chambers have to beadopted in order to obtain beverages having acceptable qualities.Thereby there are dispensing machines having two infusion chambers, tobe used based on the coffee amount to be dispensed into the infusionchamber: one with greater dimensions for greater amounts of coffee andone with smaller dimensions for beverages needing less coffee powder inthe chamber, such as for example the “ristretto” and “espresso” coffee.

However such a solution is expensive to manufacture and needs anadditional space in the dispensing machine. Furthermore, the presence oftwo infusion chambers increases the maintenance machine costsconsiderably.

Additional known problems of the dispensing assemblies refer to therepeatability of the beverage quality for all extractions.

In particular, during the “moistening” (or pre-infusion”) step,preferential paths originate inside the coffee tablet, along which theinfusion liquid can pass through the tablet more easily, with aconsequent non-optimal moistening of the coffee and a compromisedextraction of substances from the ground coffee.

Furthermore it has to be considered that some machines provide forchanges of their operative parameters based on the pressure detected onthe piston that presses the coffee powder. Then a non-homogeneousdistribution of the coffee powder inside the infusion chamber orfrictions coming from movements can provide an inaccurate reading ofpressure exercised during the coffee pressing.

Additional drawbacks caused by a non-homogeneous distribution of coffeepowder can further be a greater wear of piston which compresses thecoffee powder, with a consequent friction increase that could lead notonly to a wrong reading of the forming pressure of the tablet, but alsoto damages of the piston itself.

SUMMARY OF THE INVENTION

Object of the present invention is to solve the above mentioned problemsand to provide a process and an extracting apparatus for preparingcoffees which allow to obtain an infusion with optimal and repeatablequality of the prepared beverage, independently from the amount ofcoffee powder fed to the infusion chamber. In particular, it is anobject of the invention to provide an apparatus wherein an infusionchamber could serve for preparing beverages with very different volumes,also of one order of magnitude, such as for example 25 cc of a“ristretto” versus more than 230 cc or 12 fluid ounces (about 350 cc) ofan American coffee.

These and other objects are obtained by the present invention concerninga process for preparing coffees according to claim 1. More inparticular, the process according to the invention provides for the useof a dispensing apparatus having a supporting frame, a cylindricalinfusion chamber, with a preferably vertical axis, mounted on thesupporting frame and able to translate with respect to the frame along adirection parallel to the axis of the infusion chamber, and a feed chutemounted on the supporting frame. The feed chute can be rotated withrespect to the frame in order to feed the ground coffee to the infusionchamber and it is arranged above the infusion chamber, during at leastpart of the preparing steps of the beverage. The process comprises, in aknown way, the steps of:

-   -   a) preparing, and feeding into the infusion chamber through the        feed chute, a measure of ground coffee based on the dispensation        selection made by a user; b) compressing the coffee measure        inside the infusion chamber; and c) feeding the heated water        into the infusion chamber to prepare and dispense the coffee.

In particular, before and/or during the step a), the movable infusionchamber and/or the feed chute are arranged, one with respect to another,as a function of the amount of ground coffee of the measure to beaccommodated inside the infusion chamber. More in detail, the process ofthe invention is characterized by the steps of identifying the beveragetype selected by the user, determining the positions of said chamber, ofthe piston movable along with the chamber and of the feed chute,checking whether the positions correspond to those stored in a memorydevice of the apparatus as positions associated with the beverage to bedispensed; in case, changing the position of the chamber up it reachesthe corresponding stored position for the selected beverage; feeding therequested amount of ground coffee or other ingredient and dispensing thebeverage selected by the user. As better disclosed hereinafter, thechamber position is directly associated with the angular position of thechute, whereby in the process herein described it is sufficient todetect the position of the infusion chamber to be able to determine thechute position too. Furthermore, the position of the lower piston can beobtained from the position of the infusion chamber and the progresslevel of the process, i.e. from the knowledge of which have been theprocess steps made before.

For the purposes of the present invention, with the term “determiningthe position of the lower piston” is intended the possibility—inrelation to a certain component—of directly or indirectly determiningthe position in which said component is, that is for example bymonitoring the electric movement of a second component mechanicallyconnected to the first one.

Object of the present invention is also an apparatus for preparing anddispensing coffee, comprising: a supporting frame, a cylindricalinfusion chamber, with a substantially vertical axis, i.e. vertical orslightly tilted with an angle smaller than 10 degrees, preferablysmaller than 5 degrees and more preferably smaller than 3 degrees withrespect to the vertical; the infusion chamber is mounted on thesupporting frame and is able to move in translation with respect to saidframe along a direction parallel to the axis of the infusion chamber; afeed chute mounted on the supporting frame, arranged above the infusionchamber and able to rotate with respect to the frame itself to feed theground coffee to the infusion chamber.

The apparatus for preparing and dispensing coffee comprises means forarranging the movable infusion chamber, the lower piston and/or the feedchute, one with respect to another, as a function of the amount ofground coffee of the measure to be accommodated inside the infusionchamber, in order to have a material distribution as uniform as possiblebefore the material is compacted in the step preceding the infusion.

According to the invention, the movable infusion chamber has a pistonforming a bottom wall in the chamber; if necessary, in turn the pistonis movable in the chamber to change the volume of the chamber itself.Preferably, for each dispensation, the distance of the bottom wall ofthe infusion chamber from the upper edge of the latter is set up also asa function of the amount of ground coffee of the measure to beaccommodated inside the chamber.

According to a further aspect of the present invention, the feed chutecan be freely rotated with respect to an axis perpendicular to thetranslation axis of the infusion chamber, and the chute positioning isadjusted by means of respective cam surfaces associated with theinfusion chamber and the chute itself.

More in detail, the process provides for the movement of the chamber,its piston and chute, from a generic starting position (expressed by thecoordinates h1, h2 and α, where h1 is the chamber distance from theupper base of the frame, h2 is the distance of the lower piston from theupper edge of the infusion chamber and α is the tilt angle of the chute)and at least one final position, with which a uniform distribution ofcoffee in the chamber is obtained. Said at least one final position(expressed by the coordinates h1, h2 and α too) is stored in a controlunit in the form of a “map” experimentally obtained before; in the map,final positions (the coordinates h1, h2 and α of the positions that thechamber, its piston and chute must reach) are stored, associated with aseries of predetermined coffee amounts generally corresponding to thenecessary amount for one or more beverages. Such values are stored in amemory device readable by a control unit.

In other words, the process provides for the experimental determinationof which are the positions of the infusion chamber, its lower piston andchute (expressed as coordinates h1, h2 and α) leading to a betterdistribution of the coffee layer in the infusion chamber, i.e. adistribution as uniform as possible. It has been verified that a uniformdistribution corresponds to a better beverage dispensation from a knownand predetermined amount of ground coffee. Positions expressed ascoordinates are stored in a memory device as coordinates associated withsaid amount of ground coffee.

When a beverage is being dispensed, the control unit changes the h1, h2and α values from the current values, e.g. of the standby position, tothe values stored as adapted for the beverage to be dispensed; then thechamber, the lower piston and the chute are moved to the position h1, h2and α found in the memory and associated with the beverage type the userrequested; the ground coffee is fed into the chamber in the suggestedposition and then the former is compressed to a tablet shape before thegenerally hot water infusion.

Thanks to this solution, the pressing the ground coffee is subjected tobefore the infusion, allows to always obtain a tablet with asubstantially uniform density, that is as uniform as possible, insidethe infusion chamber.

By means of experimental tests it has been found that, in order toobtain a proper pressing, it is sufficient that the cone of powdercoffee settled in an infusion chamber reaches a maximum height, from thebase of the infusion chamber, at the center of said base; so during thepressing, grains of ground coffee are distributed inside the infusionchamber, with a substantially uniform density.

Coordinates h1, h2 and α, corresponding to position in which an amount xof ground coffee with grain size z has been detected, such an amountbeing necessary for preparing a beverage y, once that amount is fed tothe infusion chamber becoming a cone with top on the chamber axis ornext to the chamber axis, are then stored in the memory device asassociated with the requested beverage.

The same is done for other beverages the apparatus has to dispense,thereby forming a map of possible solutions. The experimentally obtaineddata can then be processed to give a function or algorithm allowing toobtain various types of coordinates h1, h2 and α, starting from groundmatter amount and grain size thereof.

When operating, once the volume of the infusion chamber has been set up,during the settlement of the ground coffee, the chamber itself and/orthe feed chute are arranged in one or more positions stored in the mapso that, at the end of the arrangement, the settled coffee powder wouldreach a maximum height of the settlement cone, substantially at thecenter of the infusion chamber, and this happens for every amountprovided for the measure determined by the selection the user did.

According to the present invention, the movable infusion chamber has atleast one lower piston wall for changing its volume and set it up,before every dispensation, as a function of the amount of ground coffeeof the measure to be housed inside it.

According to a further aspect of the present invention, the feed chuteis freely rotated with respect to an axis perpendicular to thetranslation axis of the infusion chamber (and not necessarilyintersecting the same), and the cam surfaces associated with the feedchute and the infusion chamber allow to mutually position them.

Object of the present invention is also a computer program comprisingcodes executable by a computer in order to optimize the distribution ofcoffee powder or other material in an infusion chamber of an apparatusfor preparing and dispensing coffee or other beverage according to thepresent invention.

The program is stored in a memory device and is executed by a controlunit of the apparatus for preparing and dispensing beverages accordingto the present invention; said program comprises: codes executable by acomputer for determining the positions h1, h2 and α of the infusionchamber, the lower piston and the chute; codes executable by a computerfor checking whether said determined positions h1, h2 and α correspondto positions stored in a map in the memory unit, adapted for thebeverage to be dispensed; codes executable by a computer for changing,in case, the positions h1, h2 and α of the infusion chamber, the lowerpiston and the chute up they reach the corresponding stored positions.

According to an aspect of the present invention, a code determinesdirectly and/or indirectly the coordinates h1, h2 and α by means of atleast one position sensor; a code compares the values of suchcoordinates with the values of the coordinates stored in a map in thememory unit; in case in which the stored coordinates and the determinedcoordinates are different, an additional code changes the positions h1,h2 and α by driving the motor means.

According to an additional aspect of the present invention, coordinatesh1, h2 and α optimizing the distribution of coffee powder for everybeverage dispensable by the apparatus for preparing and dispensingbeverages according to the present invention and as discussed before,are stored in the map, such coordinates stored in the map having beenpreviously obtained by means of experimental tests.

BRIEF DESCRIPTION OF THE DRAWINGS

Further aspects and objects of the present invention will become moreevident from the description below, made for illustrative and notlimitative purposes, with reference to the accompanying schematicdrawings, in which:

FIG. 1 is a front partial section view of an apparatus for preparing anddispensing coffee;

FIGS. 2, 3 and 9 show the arrangement of chamber and pistons, in a crosssection, in two steps of the invention process;

FIGS. 4A, 4B and 4C represent some steps of the chute tilt adjustment bymeans of the infusion chamber in the invention process;

FIGS. 5 and 6 are partial cross sections of the apparatus during thestep of compressing the ground coffee;

FIGS. 7 and 8 are partial cross sections of the apparatus during thestep of ejecting the tablet of ground coffee after the infusion;

FIGS. 10 and 11 show the positions of chamber and pistons during a cyclefor preparing the beverage, starting from two different initialpositions of the chamber.

MODES FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, an apparatus 1 for preparing and dispensing coffeehas a supporting frame 2 to which means necessary for preparing abeverage are constrained. In particular an infusion chamber 3, having acylindrical shape with vertical or substantially vertical axis 4 (i.e.tilted with respect to the vertical of an angle lower than 10 degrees,preferably lower than 5 degrees and more preferably lower than 3 degreesfrom the vertical) are shown, the chamber 3 being mounted on thesupporting frame 2. In particular the infusion chamber 3 can move intranslation with respect to the frame 2 along the direction of the axisof the infusion chamber 3, as shown by an arrow F in FIG. 1. Inside thechamber 3 there is a piston 12, in a known way, forming a movable bottomwall.

The apparatus 1 has further a feed chute 6 mounted on the supportingframe 2 to feed the ground coffee to the infusion chamber. The feedchute 6 is arranged above the infusion chamber 3, being able to rotatewith respect to a pivot 8 constrained to the same frame 2, as indicatedby the arrow 7 in FIG. 1.

The apparatus 1 further comprises a higher piston 14 for compressing thecoffee tablet 13; in the shown embodiment, said piston 14 is fixed, butadditional embodiments in which the piston 14 is axially movable can beprovided.

The apparatus 1 further comprises means for arranging the movableinfusion chamber 3 and/or the feed chute 6 one with respect to anotherin such a position that the ground coffee coming out from the chute willsettle on the bottom wall 12 of the infusion chamber 3 with a determineddistribution.

According to the invention, exemplified in the preferred embodimentshown in the figures, the infusion chamber 3 is mounted in a known wayon an operating worm 5 driven by motor means M1, which are schematicallyshown in FIG. 1 and cause the rotation of the worm 5 and the consequentvertical translation of the chamber along the axis 4. In the shownembodiment, the translation direction of the infusion chamber 3 isparallel to the axis 4 of the infusion chamber 3 itself. Motor means M1are able to accurately carry out little displacements of the infusionchamber 3 where, with the term little, movements of about a tenth ofmillimeter is intended. For example motor means M1 can comprise astepper motor acting on the operating worm 5 coupled to a nut screw orsimilar means, integral with the chamber 3.

As mentioned above, the feed chute 6 can be rotated with respect to theaxis of the pivot 8, which is preferably mounted perpendicularly to thetranslation axis of the infusion chamber, but preferably notintersecting therewith. The chute 6 is mounted symmetrical to therotation pivot 8, so that it is usually urged by its own weight torotate towards the upper piston 14; as shown in FIG. 1, the chute 6 isarranged on a side of the second cylinder, and it extends through theupper portion 19 of the frame up to an arm 6′ that, in its turn, extendsup to the mounting point composed of a pivot 8 at the opposite side withrespect to the axis 4.

The chute 6 comprises a drop or slip plane P intercepting the axis 4with an angle α (upper angle); supposing a as a constant, based on theposition of the chamber 3 and the lower piston 12, the plane Pintercepts the wall inside the chamber or piston 12 in differentpossible positions. Plane P is defined by the last chute portion or, ifsuch a portion is curved, the plane is that extending between theinitial and final parts of said curved portion.

For practical purposes, the plane P is assumed as corresponding to theideal slip direction of the coffee powder, the direction beingrepresented by the straight line tangent to the path of the parabolicmotion (under the gravity action) of the coffee powder in the endingchute point.

The position of the infusion chamber is defined by the distance h1(FIG. 1) between the lower side of the upper base 19 of the frame 2 andthe upper edge 15 of the infusion chamber 3. The position of the lowerpiston 12 is defined by the distance h2 (FIG. 3) between said piston 12and the upper edge 15 of the infusion chamber 3. The three height andtilt values h1, h2 and α are the coordinates identifying the position ofchamber, piston and chute and the possible path of the ground coffee.

All three afore described values, i.e. α, h1 and h2, can be changed toadjust the ideal interception point of the plane P with the infusionchamber so that to obtain a regular distribution of coffee inside thechamber itself. Such an ideal distribution is as uniform as possible, sothat to obtain a tablet thickness, after the compression, that is asuniform as possible too. An ideal shape of uniform distribution is thatin which the highest point (top) of the cone, made of coffee fed intothe chamber, lies on the axis 4 or immediately adjacent thereto.Alternatively two or more cone tops are possible, equal one to anotherand spaced out from the chamber; these can be obtained by changing thecoordinates h1, h2 and α during the dispensation of ground coffee.

According to the present invention, the adjustment of coordinates h1, h2and α is made by an open loop control; the h1, h2 and α values leadingto an uniform coffee distribution in the chamber, are obtained byexperimental tests and stored in a map; the stored h1, h2 and α valuesare experimentally obtained for a series of specified coffee amountsgenerally corresponding to the amount necessary for at least onespecified beverage. In other words, a certain number a determined coffeeamounts are selected, e.g. equal to 4.0 g, 8.0 g, 11.0 g and 14.0 g,corresponding to as many beverages (strong, espresso, weak, Americancoffee), the coordinates h1, h2 and α are experimentally obtainedleading to an optimal distribution of powdered coffee and suchcoordinates are stored in a map of a control unit in combination withrespective beverages and amounts of coffee to be delivered.

Every map stored in the control unit is anyway referred to a particulargrinding coffee degree and/or a particular coffee body; in general thecontrol unit stores at least one map in which coordinates h1, h2 and αto be reached by the infusion apparatus during the whole preparing cycleof one or more beverages are stored.

As the beverage is dispensed, for example a weak coffee, the controlunit 21 monitors the coordinates h1, α and h2 of the chamber, chute andpiston by their determination in a known way (for example by means ofposition sensors, encoders on the worm 5 or similar devices); then thecontrol unit drives the motor means M1, by a closed loop control, todisplace the infusion apparatus from a general initial position to adetermined position having the coordinates h1, h2 and α stored asadapted for the beverage to be dispensed; the ground coffee is then fedto the infusion chamber; the control unit can have in memory additionalpositions and then additional coordinates h1, h2 and α the infusionapparatus must reach during the feed step; subsequently the powderedcoffee is compressed to a tablet before the generally hot waterinfusion.

The same operations are repeated for the next beverage.

In the preferred embodiment shown in the figures, α, h1 and h2 valuescan be changed by the chamber translation; directly regarding to h1 andindirectly regarding to h2 and α.

Regarding to the change of α angle, the invention provides that thelower edge of the chute is shaped so that it can be rotated by the pushof the translating chamber 3; for this purpose chute and chamber havepreferably cam means. More in detail, the chamber 3 has on top and in aknown way, ejecting means 11, for example rotatable around an axisparallel to axis 4, to remove the tablet of exhausted coffee when thedispensation is ended. Cam surfaces 9, 10 are respectively provided onejecting means 11 associated with the infusion chamber 3 and on the feedchute 6, so that their engagement will cause a displacement of the feedchute 6 with respect to the infusion chamber 3 and then a change of theα angle.

As can be seen in FIG. 4A-4C, referring to the shown embodiment, araising of the infusion chamber 3, then a decrease of the distance h1,causes the engagement of the cam surface 9 with the cam surface 10 ofthe feed chute 6, and a consequent anticlockwise rotation of the feedchute 6 around the pivot 8 and a decrease of the α angle. On thecontrary, a lowering of the infusion chamber 3, then an increase of thedistance h1, causes a clockwise rotation of the feed chute 6 and then anincrease of the α angle. A further lowering of the infusion chamber 3causes the disengagement of the cam surfaces 9 and 10, so that todecouple the movement of the feed chute 6 from the movement of theinfusion chamber 3 itself and to be able to freely position the latterwith respect to the former. It is evident than different positions ofthe cam surfaces 9 are possible, as long as able to cooperate with thecam surface 10 of the feed chute 6.

In the description herein represented cam means 9, 10 have beendescribed for the handling of the feed chute 6, freely to rotate,through the movement of the chamber 3, but different handling means canbe adopted, for example motorized handling means known in the art fortheir controlled positioning of the feed chute with respect to theinfusion chamber.

According to a peculiar aspect of the invention, the infusion chamber 3has a lower piston forming at least one movable bottom wall 12, from nowon simply lower piston 12, that allows to change the volume of thechamber 3. The lower piston 12 is integral with a column, or stem, 12′protruding from the lower part of the chamber 3. As afore mentioned, theposition of the lower piston 12 can be defined by the distance h2between said lower piston 12 and the upper edge 15 of the infusionchamber 3.

In the preferred shown embodiment, the position h2 of the piston isadjusted by the translation of the infusion chamber; in otherembodiments motorized means for adjusting the h2 value can be present.

For example, starting from an initial position shown in FIG. 9, in whichthe chamber is completely raised and the lower piston 12 is completelylowered into the chamber 3, h2 is equal to its maximum value; in orderto decrease the distance h2, i.e. to displace the lower piston 12towards the upper edge 15 of the infusion chamber 3, the infusionchamber is translated downwards until the column 12′, by abuttingagainst the lower base 17 of the frame 2, will hold the lower piston 12in a fixed position and the descending infusion chamber 3 will reducethe distance h2 to the desired one, e.g. half of distances in FIG. 9.

When the infusion chamber is translated upwards, the lower piston stayson the previously assumed position by friction means 23 and 24, forexample gaskets, that prevent said lower piston from freely slide insidethe infusion chamber; said friction means can be, for example, O-rings.

FIG. 2 shows the position in which h2 is equal to 0, because bothchamber 3 and piston 12 have been displaced to their maximum lowerposition, in abutment against the lower frame base. Starting from theinitial position shown in FIG. 2, in which the lower piston 12 is flushwith the upper edge 15 of the chamber 3 and h2 is equal to zero (itsminimum value); in order to increase the h2 distance, the infusionchamber 3 is translated upwards so that the lower piston 12, by abuttingagainst the upper piston 14, is stopped and held in a fixed position,whereas the ascending infusion chamber 3 will increase the h2 distance.

Additional embodiments are anyway provided, in which the position of thelower piston 12, i.e. the distance h2, can be adjusted by handling saidlower piston by dedicated motorized means known in the art.

The control unit 21 determines the positions of the chamber 3, lowerpiston 12 and chute 6 through at least one of the values of coordinatesh1, h2 and α; for the purposes of the present invention, the h2 positionof the lower piston 12 is determined by drawing it from the coordinateh1 relative to the position the infusion chamber takes during theoperating cycle. In other words, starting from an initial referringposition h1 in which, e.g., the infusion camber is completely lowered(compare position A of FIG. 10), such a starting coordinate h1corresponds to a h2 coordinate equal to zero as the lower piston 12 isflush with the upper edge 15 of the chamber 3; then, starting from thiscycle step, it is possible to translate the infusion chamber to a finalheight h1, so that the lower piston 12, by abutting against the upperpiston 14, will reach the desired height h2 thereby determining h2 fromthe detected height h1.

Similarly, starting from a referring position h1 in which, e.g., theinfusion camber 3 is completely raised (see FIG. 9), in such a cyclestep the starting coordinate h1 corresponds to a known coordinate h2equal to its maximum value, as the lower piston 12 is completely loweredinside the chamber 3; then, starting from this cycle step, it ispossible to successively translate the infusion chamber to a finalheight h1, so that the column 12′ of the lower piston 12 abuts againstthe lower base 17 of the frame 2 and the lower piston 12 reaches thedesired height h2 thereby determining h2 from the detected height h1.

It has to be noted that the h2 value can also be determined by detectingthe position of a point of the column 12′, for example the end, and theposition of the chamber 3, i.e. h1. Knowing how much is the distancebetween the end of 12′ and the end of the piston 12 it is possible todetermine the h2 value.

Alternatively, the h2 position of the lower piston can be adjusted, withrespect to the infusion chamber, by dedicated motorized means of a typeknown in the art and, in this last case, h2 can be detected by positionsensors known in the art coupled with such motorized means.

As described before, in the preferred embodiment shown in figures, alsoangle α is set up as a function of h1; this allows to obtain a change inthe intersection point between the plane P and the inner wall of thechamber or piston 12 greater than an embodiment in which the angle α isadjusted by leaving h1 constant. In general, the intersection pointbetween the plane P and the inner wall of the chamber or piston 12 canbe displaced, for example towards the chute, by leaving the angle αconstant and decreasing h1 (by translating the chamber upwards), or elseby leaving h1 constant and decreasing a (by the chute rotation).

Referring to FIGS. 4A-4C, in the shown embodiment, a decrease of h1involves automatically a decrease of a and similarly an increase of h1corresponds to an increase of the α angle; then it is possible torapidly obtain a displacement of the intersection point between theplane P and the inner wall of the chamber or piston 12 by means of alittle and accurate rotation of the stepper motor corresponding to achange of h1 and then of α.

Analogously to h2, an α angle can be determined too by appropriateposition sensors known in the art or obtained from the h1 distance.

As afore mentioned, an ideal shape of uniform distribution is that inwhich the highest point (top) of the cone, made of coffee fed into thechamber, lies on the axis 4 or immediately adjacent thereto. Based onthis visual observation, or other observations that can be visual ornot, such as for example a coffee layer with a substantially constantthickness, and/or the dispensing beverage times, and/or the organolepticcharacteristics of the dispensed coffee (that is the final beverage), itis possible to proceed with the construction of “maps” in which thepreferred coordinates requested for every measure of coffee are stored,so as to have the requested distribution of powdered coffee into theinfusion chamber.

This allows the use of an infusion chamber with relatively greatdimensions also with very reduced amounts of powdered coffee, withoutlosing the quality of the dispensed beverage.

Then, during the map construction, the coordinates h1, h2 and α arestored with which a determined distribution of powdered coffee settledin the infusion chamber is repeatably obtained; the particularembodiment shown in figures allows to determine and adjust h2 and αthrough h1, thereby embodiments are provided in which the realized mapsare easier and in which only the coordinate h1 of the position, or of aseries of positions (coordinates h1) that the infusion chamber has toreach for every coffee amount and then for every beverage selected by anuser, is stored; in this embodiment the values assumed by a based on h1and at least the value of h2 at the beginning of the cycle, are anywayknown.

In practice, during the map construction, it is possible to determinethe experimentally obtained h1, h2 and α values and to store them intothe map; or else it is possible to detect only the h1 values anddetermine the h2 and α values, by drawing them from h1, then store suchcoordinates into the map; or else to detect and store the h1 coordinatesonly, that is all positions the infusion chamber will have to adoptduring the whole cycle for preparing the particular beverage selected bythe user, starting from a known value of h2 at the beginning of thecycle.

Referring to FIGS. 2-8; the beverage preparation steps are nowdescribed.

At the beginning a user of a machine comprising an apparatus 1 accordingto the present invention, selects the dispensation of a coffee typethrough known methods.

The control unit 21 monitors in a known way (for example by means ofposition sensors, encoders on the worm 5 or similar devices) thecoordinates h1, h2 and α of the chamber 3 of the piston 12 and chute 6.

Then, before feeding by gravity the selected measure of ground coffeeinto the infusion chamber 3, the control unit 21 selects, from thestored map, the coordinates h1, h2 and α the infusion apparatus willhave to reach during the whole operating cycle.

At the beginning the control unit acts on the motor M1 of the apparatus1 to adapt the volume of the infusion chamber (height h2) to theselected typology of coffee selected by the user.

As mentioned before, the adjustment of h2 can be carried out in a numberof modes, for example through appropriate motors. In the exemplaryimplementation shown in figures, usually the adjustment of h2 is carriedout starting from an initial configuration of chamber 3 that is the oneshown in FIG. 7. As a matter of fact, this is the position the chamberassumes at least during the ejecting step of the exhausted tablet ofcoffee; the lower piston 12 of the infusion chamber 3 is raisedsubstantially flush with the upper edge 15 of the infusion chamber 3 andthe column 12′ of the piston is in abutment against the lower base 17 ofthe frame 2.

In this reference position, h1 corresponds to a coordinate h2 equal tozero because the lower piston 12 is flush with an upper edge 15 of thechamber 3; referring to FIG. 2, in order to adjust the volume of theinfusion chamber, the chamber is translated until the upper piston 14 isin contact with the lower piston 12 and has been pushed inside thechamber; the chamber is translated up to reach a position h1 that can bepresent in the memory or anyway calculated from the value of the desiredcoordinate h2.

Such a final position is reached through a closed loop control carriedout by the control logic that monitors, in such a way, the h1 positionof the chamber and drives the motor means M1 until h1 will reach thevalue stored in the map. The position h1 of the chamber is detected bymeans of position sensors, encoders on the worm 5 or similar devices.

Alternatively, the adjustment of h2 is carried out starting from aninitial configuration of chamber 3 that is the one shown in FIG. 9. Inthis configuration the chamber is completely raised and the lower piston12 of the infusion chamber 3 is completely lowered; in this startingconfiguration, the coordinate h1 and the coordinate h2 are known (equalto their minimum and maximum value, respectively).

Referring to FIG. 9, in order to adjust the height h2, the chamber islowered so that the column 12′ of the lower piston 12 abuts against thelower base 17 of the frame 2 and the lower piston 12 reaches the desiredheight h2; for this purpose the chamber is lowered up to reach aposition h1 that can be present in the memory or anyway calculated fromthe desired value h2. Such a final position h1 is reached by a closedloop control similar to that described before.

Once the volume has been set up, the infusion chamber 3 is thentranslated to reach an addition position h1 stored in the map; in such aconfiguration, the chamber is positioned underneath the feed chute 6 andthanks to the mutual engagement of the cam surfaces 9 and 10, such aposition h1 corresponds to a desired angle α of the feed chute 6; infact, as afore mentioned, every a value obtained during the mapconstruction corresponds to a stored value h1.

Then, when this h1 value and consequently a determined angle α will bereached, as illustrated in the sequence of FIGS. 4A-4C, it is possibleto feed the ground coffee, as schematized in FIG. 5. Thanks to theoptimal positioning between the infusion chamber 3 and the chute 6, adistribution as homogeneous as possible of ground coffee inside thechamber 3 is obtained.

In the memory map is anyway provided the possibility of havingadditional α angles (then additional h1 positions) the chamber will haveto reach in determined time ranges during the feeding of ground coffee.In other words, during the feeding of ground coffee into the chamber,usually happening during the grinding of coffee beans, the control logiccan drive the motor means M1 and change the angle α based on additionalh1 values present in the stored map; to reach such stored coordinates,the control unit can stop the grinding during the chamber translation,or else translate the chamber during the grinding and then the coffeepowder settlement.

When the feeding step is ended, the infusion chamber 3 is then raisedagain towards the piston 14, as shown in FIG. 6, to compress the groundcoffee and form the so-called “tablet” 13. The lower piston 12 is thenpushed by the piston 14 until it stops next to the lower edge 16 of theinfusion chamber 3, position in which the piston 14 applies the pressurenecessary to compact the ground coffee and form the tablet 13.

In the shown position of FIG. 6, the beverage infusion happens, that isthe feed of water into the infusion chamber 3 through a radial inletduct (not shown) communicating with the lower part of the infusionchamber 3. Then the infusion liquid passes through the infusion chamber3 so that to extract the substances from the tablet 13 of ground andpresses coffee. An outlet duct 20 allows the beverage to be dispensed tothe user.

In FIGS. 7 and 8, the operations for the removal of the exhausted table13 are shown. The infusion chamber 3 is moved away from the piston 14towards its own position A of FIG. 10 with h2 equal to zero, as shown inFIG. 2. In particular, the infusion chamber 3 is completely lowered, sothat the column 12′ of the lower piston 12 will abuts against the lowerbase 17 of the frame 2, thereby moving the lower piston 12 at the upperedge 15 of the infusion chamber 3, as shown in FIG. 7 (h2 equal tozero).

Afterwards, as illustrated in FIG. 8, the chamber 3 is translatedupwards up to reach the discharge position shown in FIG. 8 (position iof FIGS. 10, 11). Once this position is reached, the ejecting meansremove the tablet 13. In the herein described embodiment, the ejectingmeans are composed of a paddle 11 rotatable around an axis 18 to remove,because of its rotation, the tablet 13 from the lower piston 12 in araised position. Once the tablet 13 has been removed, the initialcondition is created again and a new preparing and dispensing cycle ofcoffee can start.

In FIGS. 10 and 11 a dispensing cycle of the beverage, showing theposition that chamber and piston can assume one with respect to another,is shown. The cycle of FIG. 10 starts from an initial position in whichchamber and piston are in their lower positions, the cycle of FIG. 11starts from a position in which chamber and piston are in their upperposition (similarly to FIG. 9).

For illustrative and non-limitative purposes, values of coordinates h1,h2 and α will follow, obtained during experimental tests, that optimizethe coffee distribution in an infusion chamber having a diameter equalto 45 mm.

-   -   Measure 4 grams: h1=106 mm, h2=36 mm; α=27°;    -   Measure 8 grams: h1=109.5 mm, h2=42 mm; α=27°;    -   Measure 14 grams: h1=104.5 mm, h2=44 mm; α=26.2° (for the first        6 seconds);        -   h1=109.5 mm, h2=44 mm; α=27° (for the following 4 seconds).

The invention claimed is:
 1. An apparatus for preparing and dispensingcoffee or other beverage by infusion of a material, said apparatuscomprising: a supporting frame (2), a cylindrical infusion chamber (3)with a substantially vertical axis (4), said chamber (3) being mountedon said supporting frame (2) and able to move, by a motor, intranslation with respect to said frame (2) along a direction parallel tothe axis of the infusion chamber, a lower piston (12) forming a bottomwall in said chamber, said wall being movable in said infusion chamber(3), a feed chute (6) mounted on said supporting frame (2) which is ableto rotate with respect to said frame in order to feed ground coffee tosaid infusion chamber (3), a higher piston (14) for closing saidinfusion chamber during the beverage infusion step, characterized inthat said apparatus comprises a control unit provided or connected witha memory (22), wherein a plurality of positions of said chamber (3),said lower piston (12) and said chute (6) are stored; and in that saidapparatus further comprises means for determining a position of each ofsaid chamber (3), said lower piston (12) and said chute (6); means forchecking whether coordinates α, h1 and h2, the coordinates obtained bythe position-determining means, correspond to coordinates stored in saidmemory associated with the selected beverage; and means for changing theposition of the chamber (3), the lower piston (12) and the chute (6) inresponse to the coordinates obtained by the position-determining meanscorrespond to the stored coordinates adapted for the beverage to bedispensed.
 2. The apparatus according to claim 1, comprising means fordetermining the coordinates α, h1 and h2, where α is the tilt angle ofsaid chute (6) with respect to said chamber axis (4), h1 is the distanceof the chamber (3) from the upper base (19) of said frame (2) and h2 isthe distance of said lower piston (12) from the upper wall (15) of saidinfusion chamber (3).
 3. The apparatus according to claim 1, whereinsaid feed chute is mounted on a point of said frame and rotatable withrespect to an axis perpendicular to the axis (4) of translation of saidinfusion chamber, in order to change the tilt of the chute itself withrespect to said infusion chamber (3), and wherein said chute comprisesan arm extending above said frame from said mounting point to saidchute.
 4. The apparatus according to claim 3, wherein respective camsurfaces (9, 10) are provided and associated with said feed chute (6)and said infusion chamber (3) in order to position said chute withrespect to said chamber.
 5. The apparatus according to claim 4, whereinthe cam surfaces (9, 10) associated with said infusion chamber arearranged on the upper edge of means (11) ejecting a coffee tablet afterthe infusion.
 6. The apparatus according to claim 1, comprising at leastone sensor for detecting the position of the chamber (3).
 7. A computerprogram comprising codes executable by a computer for optimizing thedistribution of powdered coffee or other material in an infusion chamberof an apparatus for preparing and dispensing coffee or other beverageaccording to claim 1, said program being stored in a memory unitreadable by a computer and comprising: computer executable codes fordetermining the positions of said chamber (3), said lower piston (12)and chute (6), computer executable codes for checking whether saidpositions correspond to those stored in said memory (22) as adapted forthe beverage to be dispensed; computer executable codes for changing, incase, the position of the chamber (3) and the position of the lowerpiston (12) up they reach the corresponding stored positions for theselected beverage.
 8. The program according to claim 7, furthercomprising computer executable codes for determining the values h1, h2and α, where α is the tilt angle of said chute (6) with respect to saidchamber axis (4), h1 is the distance of the chamber (3) from the upperbase (19) of said frame (2) and h2 is the distance of said lower piston(12) from the upper wall (15) of said infusion chamber (3).
 9. Theprogram according to claim 8, further comprising computer executablecodes for determining the values h1, h2 and α corresponding, for adetermined coffee amount, to a chamber position in which the requireddistribution of coffee into said chamber (3) is obtained.